This invention relates to transmission of data and in particular to the telemetering of biomedical data of a patient to a monitor for display.
Telemetry systems are now being widely used clinically to monitor post surgical patients and cardiac patients. Typical commercial systems are single channel and are used for ECG monitoring. Some experimental multichannel systems have been reported in literature for use in surgical monitoring and intensive care monitoring. These systems propose a voltage controlled oscillator for each channel with an FM modulated carrier which is demultiplexed at the receiving end utilizing band pass filters and frequency discriminators. Other systems have used pulse width modulation or other conventional modulation formats, and several multichannel systems are now available commercially. Also, systems providing a plurality of data channels for direct connection between a plurality of transducers and/or sensors and a monitor are available commercially.
It is an object of the present invention to provide a new and improved telemetering system especially suited for use with a medical patient and providing a plurality of data channels. A further object is to provide such a system which can be interposed between the conventional transducers and the conventional monitor without requiring changes or adjustments of either. A further object is to provide a telemetering system for a resistance value with the output simulating the resistance at the input so that the monitor operates the same with direct transducer connection and telemetering system connection as input.
It is a particular object of the invention to provide a telemetering system for transmitting a pressure wave such as a recurring pulse pressure wave, providing for transmission of the waveform and values of the peak and trough corresponding to the systolic and diastolic pressures, respectively. An additional object is to provide a telemetering system for transmission of a temperature value with high resolution and high accuracy and low drift so that introduction of a telemetering system does not introduce any additional error in the overall measurement.
These and other objects, advantages, features and results will more fully appear in the course of the following description.